Fluid transfer apparatus



.June 30, 1942. w. T. TABB 2,287,841

FLUID TRANSFER APPARATUS Filed Oct. 22., 1940 2 SheetsfSheet l f '.2 5141 2 fr@ 40 5 4 53 5s 5457 June 30, 1942.

W. T. TABB FLUID TRANSFER APPARATUS Filed Oct. 22, 1940 2 Sheets-Sheet 2f- BY y rnl WVM ATTORNEYS phragm only inwardly.

Patented June 30, 1942 2,287,841 ramp TRANSFER APPARATUS Warner T.Talib, Brooklyn, N. Y., assignor, by mesne assignments, toReconstruction Finance Corporation, New York, N.

. the United States Y., a corporation of Application October 22, 1940,Serial No. 362,179

17 Claims.

The present invention relates to fuid transfer apparatus andmoreparticularly to pump apparatus adapted to effect transfer of uidseither liquid or gaseous for a variety of purposes.

V General objects of the inventionare the provisions of such apparatuswhich is of simple and economical construction with minimization ofleakage tendencies, requires littleif any carefulv and costly machiningand treating of cooperating parts frictional engagement between which isrelatively minimized thus reducing tendency of wear which mighteventually require replacements or repair, can be readily and easilyassembled and disassembled, is eicien't in operation to transfer fluideiectively at a relatively uniform rate with surging and pulsation ofpumped medium reduced to a minimum, and is capable of eilicient highfrequency operation; and structural embodiments of such apparatus whichcan readily and economically be made and assembled in mass productionwhile assuring eiclent use and operation thereof,

More specic objects of the invention are the provision of such apparatuscharacterized by a pump chamber 'formed b y cooperation of a casing anda diaphragm having lateral rigidity and certain spring characteristicswith diaphragm biasing leaf-like spring structure having certain springcharacteristics mounted in the cham-` ber in a manner to provide certainnet spring characteristics for combined diaphragm and springconstruction; and to provide such apparatus wherein the mounting andcharacteristics of said diaphragm structure are such that an outwardlyprojecting diaphragm operating member mounted on the diaphragm isproperly andeiciently guided in its operation without necessitating usetherefor of bearing supports or like guiding means whichmight tend tointroduce undesirable problems o f construction, manufacture and wear;and which assure efficient operation of said apparatus by mechanicalmeans that may tend in operation to iiex said dia- Another object of theinvention is the provipast a diaphragm biasing spring disc structuresubstantially horizontal and the pump chamber thereabove which may betermed the vertical pump position, it is particularly effective forcontinuous eicient operation when mounted in suchvertical pumppositiongthe casing structure defining at least a portion of the pumpchamber, the inletand outlet passages. communicating therewith andvalves structures in the passages being such and cooperating in a manneras to assure effective escape of indrawn relatively light foi-.eign uid,such as air o r gaseous liquid when a liquid, e. g. hydrocarbon fuel, isbeing transferred by the pump.

A still further object of the invention is to provide such diaphragmpump apparatus of such construction as to permit easy and economicalprovision of simple and effective priming means,

manually operable if desired, which requires no particular provision ofpackingto prevent leak-v age, which can be simply mounted and de-4mcunted without affecting assembly of other parts, and'which can bemanipulated effectively to discontinue transfer operation of the pumpapparatus without disturbing mechanical means effecting such transferoperation. A

'.An additionalobject of the invention is the provision of suchdiaphragm pump apparatus characterized by effective provision in theinlet and/or outlet passages of simplified pulsation' eliminating meanswhereby surging of and pulsations in supplied and/or delivered fluid,such as liquid fuel, is effectively minimized assuring eflicient andrelatively uniform supply and/oi` delivery thereof.

Other objects of the invention will in part be;

obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction,combination of elements and arrangement of parts, which will beexemplified. in the construction hereinaftervsety forth and the scope ofthe-invention will be indicated in the claims. l

For a fuller understanding of the nature and objects of thevinvention,reference should be had to the following detailed description taken inconnection with the accompanying drawing, in

within the pump chamber of such a diaphragm pump, either through 'thediaphragm or around the periphery thereof, which assures' eilicient useandroperation thereof.

A further object of the invention is to provide suchdiaphragm pumpstructure which, though adapted to' effect operation when mounted in aposition other than with the diaphragm thereof which:

Fig. 1 is ,a top plan view of one embodimentof the apparatus of thepresent invention;

Fig. 2 is a sectionalview taken on line 2-2 of Fig. 1;

Fig. 3 is a top plan view of the structure shown in Figs. 1 and 2 butwith parts removed and broken away; and

desired biasing action. ture has certain spring characteristics as doesFig.'4 is a sectional view taken on line 4-4 of Fig. 1.

Various diaphragm pump structures have been v proposed for use intransferring fluids, both gaseous and liquid. For example, suchstructures have been proposed for use in both mechanical and electricalgasoline injection systems as well as for use in fuel supply systems ofinternal combustion engines of the Diesel type, oil burners and thelike. Many of such structures, however, have been of such constructionas to require extremely careful and costly machining and fitting ofparts, treating of material to'harden frictionally engaging parts, andcostly and frequently inefficient provisions of packing to preventleakage; and have been complicated making assemply and disassemblydiiiicult, subject to wear of frictionally engaging parts making repairor replacement of parts eventually necessary, and inefficient andnon-uniform in operation, Further, such structures have been such as tomake their use in systems requiring high speed operation, for examplefuel supply systems for internal combustion engines, extremely uncertainand unsuitable.

These and other difliculties are efficiently alleviated by the apparatusof the prent invention which `has been found to be highly satisfactoryfor use, by way of example. in fuel supply systems for Diesel engines.I'he diaphragm pump structure of the invention has no working partscharacterized by frictional engagement of guiding bearings, other than aroller, if desired, used as a cam follower to impart movement to adiaphragm operating member or rod. IThe diaphragm operating member ispreferably anchored to the diaphragm to project voutwardly therefromfree from any bearing support. It is guided.

in its operation solely by the diaphragm having lateral rigidity mountedwith peripheral portions thereof seated on a casing cooperating with`the former to form a chamber. A leaf-like spring structure is mountedin the chamber with outer portions thereof rigidly supported by thecasing and forms a biasing abutment for the central portion of thediaphragm structure t'o obtain the 'I'he diaphragm structhe spring'structure and these are so correlated as to give netspring'characteristics for the combined spring and diaphragm structuresas to make for desired action.

Such spring structure may be in the form of one or more laminae of sheetmetallic material of any suitable configuration such as a hub portionwith two or more, radiating arms but preferably comprises one or morediscs of spring steel or the like, preferably cup-shaped. When suchdiscs are used'provision is made for pas-y sage of fluid therepast byany suitable means such as apertures or cut-outs therein but preferablyby providing in the casing a series of spaced apart seats around thecircumference thereof with intermediate passage spaces.

The diaphragm structure preferably comprising one or more discs of steelor other resilient metallic material having desired lateral rigidity maybe assembled on or anchored to the operating member in any suitablemanner but prefer-V ably is centrally apertured to receive the inner endof the operating member or rod which projects therethrough to receive anut or collar,

The central-portion of the spring structure, to form a biasing abutmentfor the diaphragm structure, may be secured centrally to the dia.-

phragm structure in any suitable manner and have lateral clearance withits supporting means but for simplicity of manufacture and assembly itis preferred to provide a central hole in the spring structure whichreceives with clearance the projecting end of the operating rod or thenutA or collar anchoring the latter in position.

Inlet and outlet passages having valves therein are provided in thecasing to communicate with the pump chamber. The apparatus may be usedefficiently in a variety of positions but preferably is mountedvvertically with the passages communicating with the chamber through thetop of the casing and the valves therein positioned angularly withrespect to each other. The

portions of the seats of said valves, preferably of the check valvetype, nearest each other are at highest elevation with -that of theoutlet valve above that of the inlet valve. This permits effectiveescape at each pump cycle of indrawn relatively -light foreign iiuid,such as air and gaseous fuel4 when liquid fuel is being transferred,whereby tendency to build up in the pump chamber a body of such foreignfluid or gaseous matter that might eventually prevent efficientoperation of the pump is eliminated.

Provision is made for manually or otherwise priming'the apparatus. Thisis accomplished by means exterior of the chamber whereby necessity forpacking and tendency of leakage are eliminated. Suitable mechanismpermits raising or moving inwardly the diaphragm operating member.'Preferably a member or shaft is rotatably mounted on the apparatusexteriorly of the chamber preferably on a base member supporting thediaphragm and casing. 'Ihe inner end thereof may \.be provided with acam or the like or so shapedas to engage means such as ashoulder on theoperating rodrto impart to the latter the desired movement when thepriming member or shaft is rotated. When operating the apparatus by acam with the outer endof theoperating rod biased .to the externalsurface thereof to act as a cam follower the priming mechanism may beutilized to arrest uid transfer operation of the apparatus merely byrotating the shaft and holding it in rotated position to raise the camfollower free from the cam and hold itin raised position.

When the apparatus is used for transferring liquid it is desirable toeliminate pulsations or surges in delivered uid and/or in .liquid beingsupplied to the diaphragm pump. Pulsations or surge's in deliveredliquid might interfere with required degree of uniformity of feed andsimilar pulsations in the supply might interfere with efllcientoperation of the transfer pump. Should the pump be operated at timeswhen pulsations were building up pressure in the 4supply to the pump andat other times when pulsations were reducing the pressure the transferoperation of the pump might well vary, affecting delivery of fluidundesirably. Pulsations are effectively eliminated by the apparatuswiththe provision of means each comprising a flexible diaphragm backed by abody oi' trapped gas forming a portion of the wall of the duid passagenear the valve in the passage. As pointed out previously such provisionmay be made in either or both the inlet and outlet passages.

Referring to the drawings like numerals refer to like parts throughout.A base member or plate I0 is provided with an annular seat I I uponwhich seats the periphery of a diaphragm i2. 'I'he diaphragm i2 maycomprise one or more with the seat on the base I to clamp the diaphragmI2 and gaskets I3, 'I3 therebetween in a l fluid-tight manner, suitablescrews |6-I6 being used to clamp the parts together.

An operating member or a rod |1 is anchored centrally to the diaphragmI2 to project outwardly therefrom. This member preferably comprises afork I8 between the legs of which is rotatably mounted a roller I9constituting a cam follower adapted to ride on the outer surface of acam 20. A ange 2| at the base of the operating member I1 provides abearing shoulder for a central portion of the diaphragm |2 and an innerstud end 22 thereof projects through a central aperture in the diaphragmI2 and is externally threaded to receive a nut 23 between which and theange 2| is clamped the diaphragm structure with aninterposed washer 24and suitable gasket rings 25,25.

The base member I0 is provided centrally with a. hole 26 larger than theoperating rod I1 and the roller I9 carried thereby to permit without lcontact free reciprocation of the latter therethrough.

The diaphragm I2 and the casing |4 cooperate to provide a pump chamber21 on the side walls of which are formed a plurality of vcircum-`ferentially spaced seats 28-28 providing a plurality'of intermediateuidpassages 29-29 past the seats 28-28. A diaphragm biasing leaf-likespring structure 30, preferably formed of one or more laminae of sheetsteel of disc configuration is mounted in the chamber 21 with itsperiphery supported on the seats 28-28 preferably with at leastsmall'lateral clearance. This spring structurel 30 ls provided with acentral mum iiexure of the diaphragm, such as the innermost position ofthe diaphragm and associated parts of the structure shown in thedrawings. Further in such a structure those characteristics may tend toprevent the cam follower from eiectively following the cam in theoutermost position of the diaphragm. The plotted curve of those4diaphragm characteristics is found to be of great curvature indicatingthat the rate of change of positive and negative pressures may be of anobjectionable degree under certain conditions making it advisable to usevery small diaphragm deflections.

This may be compensated for or eiectively corrected by the use of auinitially cupped spring which has a reverse spring characteristic curve.Net spring characteristics of the combination oi such diaphragm andspring structure can thus be obtained which will assure approximatelyuniform pressure of the cam follower on the cam. Even a less pressure intheinnermost position of the diaphragm than in the neutral or outermostpositions thereof, or greater pressure in the latter position than whenin the neutral position, may be attained by proper predeterminedcombinations. present pump construction while making 'for simple andcompact pump construction assures long life for the diaphragm and itsoperating mechanism and efficient pump performance with the use of'diaphragm and biasing spring structureof simple design.

The casing I4 is provided with a pair of opposed bosses 32 and 33 havingrespectively'internally threaded recesses 34 and 35 to receive v fluidsupply and delivery conduits. The recess aperture 3| which engages overthe inner `end 22 of the operating rod and the structure mounted thereonpreferably receiving the nut 23 with at least small lateral clearance atpoints of greatest lateral dimension with the portions adjacent theaperture bearing against the washer 24 to form. a biasing abutment forthe ydiaphragm structure.

This spring structure 30 may be cupped and positioned as shown in thedrawings. Obviously the positionof the spring structure 30 may bereversed provided the seats 28-28 andthe diaphragm structure oranchorage structure of the operating rod are suitably altered toaccommodate such reversal. The position and shape of the springstructure will be largely dictated bythe results desired, the dimensionssuch as relation of thickness of spring structure to diameter, de-l greeof initial cupping, etc. For some purposes substantially at disc springstructure may be when not stressed. Equalization of -such travel v 34communicates through the passage 36 with a fluid passage chamber 31closed at the top by a removable cap 38 on the inlet side and a similarpassage 39 communicates with a similar chamber 40 closed by a similarcap 4| on the outlet side. The chambers 31 and 40 constitute the innerends of the inlet and outlet fluid passages communicating with the pumpchamber 21 through suitable valve ,structure located therein. Thesevalves preferably are of the check valve type so mounted in theirrespective chambers as to permit fluid to iiow into the pumpchamber -21from the inlet side ,and fluid to ow out of the pump chamber on theoutlet side, as indii f cated in the drawings.

The check valve 42 in the inlet chamber 31, as is more Afully describedin my `copending application Serial No.`362,l80 filed October 22, 1940,vcomprises a sleeve-like cage 43 having a seat 44 formed thereon againstwhiclris biased-a Valve plate 45 by a leaf-like spring structure. 46centrally apertured to receive a stud structure 41 preferably anchoredto the valve plate 45, with spacing means 46 interposed between thevalve plate structure 45 and the spring structure '.46

` to form opposed abutments whereby the valve results in the leaststrain onthe diaphragm. ll '.'he

use of a at spring structure assures compactness of pump construction.

A fiat or initially uncupped diaphragm, such as that shown by way ofexample in the drawings, has certain well defined characteristics as' aspring in and of itself. These are such as may tend to result inexcessive pressure of the cam follower against the cam in the positionsof maxiplate can be biased to its seat and the parts of the valveassembled in the cage 43'by a splitf ring 49 seated within a groove inthe cage 43 and bearing against peripheral kportions of the springstructure 46. The base of the cage 43 is machined out at 50 to form ataperedthroat for the valve port. y The'check valvein the outlet chamber40 is ,similar in construction to thecheck valve in the inlet chamber 31except perhaps in one particular. The check valve on the inletsideis-preferably provided with a hole 5| through the ycage 43 whichcommunicates with the annular recess A Thus the spring rigging of theditions in a highly satisfactory manner.

adjacent to and surrounding the valve seat on the chamber side thereofat substantially its highest point as shown. Such a hole having nopurpose in the check valve or the outlet passage maybe omitted. In thecrown of the domed chamber wall adjacent the tapered throat 50 of theoutlet valve cage 43 at its point of highest elevation is machined a way52 to cooperate with the surface of the throat 50 of the outlet valve.'the upwardly inclined inner surface of the pump chamber 21 and the hole5I, to provide an escape way for relatively light foreign fluid that maybe drawn into the pump chamber with the fluid being transferred, forexample, air and fuel fumes, when hydrocarbon fuel is being transferred.This will prevent undue accumulation of gaseous medium in the transferpump chamber which might tend to affect efficient operation thereof andpossibly prevent in the ultimate any transfer of fluid.

Pulsation eliminators are provided in the inlet and outlet passages byforming recesses 53,

53 in the caps 38 and 4I and trapping a body of air therein by flexiblediaphragms 54, 54 of the device all of the parts thereof can easily andreadily be assembled from the top.

In operation when the operating rod is lifted upwardly by a cam theresultant inward flexing of the diaphragm against the biasing actionofthe spring structure minimizes the space of the pump chamber and when,the cam permits the operating rod to be moved outwardly by the biasingspring structure partial vacuum is created in the pump chamber producinga differential in pressure on opposite sides of the inlet valvesufflcient to open the same and cause fluid to flow into the pumpchamber. When the operating rod is again moved inwardly the inlet valveautomatically closes, and pressure built up in the pump chamber byinward flexing of the diaphragm causes the outlet valve to unseat andfluid to be delivered through the outlet passage from the pump chamber.When the biasing spring structure is again permitted to move thediaphragm outwardly the outlet valve automatic'ally closes and the cycleis then repeated. The pulsation eliminator diaphragms 54, 54,` havingbodies of compressible fluid, such as air trapped therebehind, andforming walls of the inlet and outlet passages, effectively damppulsations in the supplied and delivered liquid, which pulsations asthrough one leg of the roller fork. A radially extending boss 59 on thebase I0 is bored to receive rotatably a shaft 60 having acircumferential groove GI in which the end of a pin or set screw 62seats to hold the shaft in position. The inner end 63 of the shaft 60 ismachined off on the top side thereof to form a pair of camming portions64, 64 one of which is adapted to bear against the shoulder 5.1 when theshaft 60 is roiated in a clockwise or counter-clockwise directionthereby to lift the operating rod and flex the diaphragm inwardlyagainst the biasing spring soas to raise the cam roller I9 from the cam20. An operating arm 65 is keyed to the shaft 60 for rotating it and acoil spring 8B around is well known tend to occur in such systemsthrough operation of transfer pumps and check valves thereof. The pumpapparatus may be manually primed by flexing the diaphragm inwardly andoutwardly a number of times, which can be accomplished by pulling on thepriming arm, releasing it and repeating the operation. Operation yof thetransfer pump may be arrested by pulling on the priming arm and holdingit.

It will be understood that the transfer pump structure of the. inventionis not limited to the use of a flat `or initially uncupped diaphragm.

the end of the shaft 60 having-one end thereof Y termined by a stud 6lbearing against4 the edge of the casing I4.

By way of example the transfer pump of the Ypresent invention may bemounted by means of mounting ears (5B-B8 on the base member Ill Y uponthe case of a high pressure injecting apparatus for feeding fuel to aDiesel engine Such injecting apparatus may comprise a plurality of highpressure injecting pump devices, one for each cylinder of the engine,all operated by a common cam. The circumferential surface of this cammay be provided with lobes equal in number tothe number of high pressureinjecting devices so that each revolution of the cam, such as 20, willresult in a number of complete transfer pump cycles equal to the numberof high pressure injecting devices each of which is operated during onecam revolution. VSuch operation obviously will be of very high frequencyand it has been found that the apparatus of the present invention withthe provision of diaphragm travel of about .0125" on each side of theneutral position will perform its functions under such con- It willfurther be noted that with such a mounting of Obviously an initiallycupped diaphragm could be used when desired, the associated structuresbeing altered in shape and/or dimensions suitably to accommodate thesame, or one might use diaphragms of other configurations, such ascorrugated, etc., when the inherent characteristics thereof contributecertain desired action. Of course such diaphragms also have definitespring characteristics and that 'which is set forth above as to netspring characteristics of combined diaphragm and spring constructions isgenerally applicable to constructions including cupped or corrugateddiaphragms, and the like. 4

The outer edge of the diaphragm may be rigidly clamped in mounted.position, or may be resiliently supported to a certain extent by the useof gaskets such as I3, I3 if formed from resilient material provided theclamping force is not so great as entirely to eliminate such feature.With the spring structure constructed and mounted asv disclosed where atleast small clearance is provided between the casing and outer edge ofthe spring structure and/or between the edge of spring structure at thecentral aperture and structure on the diaphragm received therein it willbe understood there may be some guiding action of the diaphragm flexingmechanism under certain conditions of operation.

It will thus be seen that the .objects set forth above are efficientlyattained by apparatus of the present invention and since certain changesmay be made in the above construction and different embodiments oftheinvention could be made without departing from the scope thereof, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

Having described my invention what I claim as new and desire to secureby Letters Patent, is:

1. Fluid transfer apparatus comprising, in combination, a casing, aresilient diaphragm structure having lateral rigidity and certain springcharacteristics peripherally mounted on said casing to form therewith apump chamber, an outwardly projectingv operating member rigidly mountedon said diaphragm by attachment thereto for substantial alignment ofsaid member free from any bearing support, a diaphragmbiasing leaf-likespring structure having certain spring characteristics positioned in thechamber with outer` portions thereof seated on said casing and thecentral portion thereof forming an abutment for said diaphragmstructure, and means between substantially the central portions of saidspring structure and said diaphragm structure to cause them to operatetogether to attain certain net spring characteristics.

2. Fuid transfer apparatus comprising, in combination, a casing, aresilient diaphragm having lateral rigidity and certain springcharacteristics peripherally mounted on said casingV to form therewith apump chamber, an outwardly projecting operating member rigidly mountedon said diaphragm free fromany bearing support, means secured to saiddiaphragm projecting on the chamber side thereof, and diaphragm-biasing`spring disc structure having peripheral portions thereof seated on thecasing within the chamber and its central portion engaging saidprojecting means in a manner to cause said structures to operatetogether to attain certain net spring characteristics.

3. Fluid transfer apparatus comprising, in

combination, a cupped casing, a resilient dia-4 phragm having lateralrigidity and certain spring characteristics peripherally mounted on saidcasing to form therewith a pump chamber, operating means rigidlyanchored to said diaphragm to form a member projecting into the chamberand an operating rod extending outwardly fromsaid diaphragm free fromany bearing support, and a diaphragm-biasing spring disc structurehaving peripheral portions thereof seated on the casing within thechamber and its central portion engaging said projecting member in amanner to cause said structures t0 O perate together to attain certainnet spring characteristics.

4. Fluid transfer apparatus comprising, in

I combination, a cupped casing, a resilient diaphragm having lateralrigidity and certain spring characteristics peripherally mounted on saidcasing to form therewith a pump chamber, .operating means rigidly'anchored to said diaphragm to form a member projecting into the chamberand an operating rod extending outwardly from said diaphragm'free fromany bearing support, and a diaphragm-biasing spring disc structurehaving its periphery seated on the` casing within the chamber at spacedapart points 'to form intermediate Vfluid `passages and its centralportion engaging said projecting. member in a manner to cause saidstructures to operate together to attain certain'net springcharacteristics. Y

5. Fluid transfer apparatus comprising, in

combination, a cupped casing, a resilient diaphragm having lateralrigidity and certain/spring characteristics peripherally mounted on saidcasing to form therewith a pump chamber, an operating rod rigidlyanchored centrally to said diaphragm with the inner end thereofextending through the diaphragm into the chamber and the outer endthereof extendingfrom said diaphragm free from any bearing support, anda cupped spring'disc structure having itsperiphery seated on the casingwithin the chamber at spaced apart points to form intermediate fluidpassages, said spring structure biasing said diaphragm with the innerend of said rod engaging the central portion of said disc structure in amanner to cause said structures to operate together to attain certainnet spring characteristics.

6. Fluid transfer apparatus comprising, in combination, a cupped casing,a resilient metal diaphragm having lateral rigidity and icertain springcharacteristics peripherally mounted on said casing to form therewith apump chamber, inlet and outlet valves communicating with the chamber, anoperating rod rigidly anchored centrally to said diaphragm in suchmanner as to form a projection on the chamber side thereof, said rodextending outwardly from said. dia- 'phragm free from any bearingsupport and terminating in acam follower, a pluralityV ofcircumferentially spaced seats inside the chamber, and

a cupped spring disc structureperipherally supjection engagingthecentral portion of said disc' structure in a manner to cause saidstructures to operate together to attain certain net springvcharacteristics. y

7. In uid transfer apparatus, the combination comprising a resilientdiaphragm structure having certain spring characteristicsperipherallymounted for laterally inward movement of outer portions thereof duringfiexure, means to flex said diaphragm, a diaphragm-biasing leaf-likespring structure having certain different spring characteristics mountedwith outer portions thereof supported, and thrust means betweensubstantially the central portions of said diaphragm and springstructures causing them to operate together to attain certain net springcharacteristics of the assembly making for desired action.

8. In uid transfer apparatus, the. combination comprising a resilientdiaphragm structure having certain spring characteristics peripherallymounted for laterally'inward movement of outer portions thereof duringflexure, means to iiex said diaphragm, a diaphragm-biasing leaf-likespring structure having certain spring characteristics substantially thereverse of those of said diaphragm structure mountedv with outerportions thereof supported', and thrust means between substantially thecentral portions of said dia" phragm and spring structures causing themto diaphragm structure by attachment thereto for substantial alignmentof said member free from l any bearing support, and a diaphragm biasingspring structurey positioned in the chamber with outer portions thereofseated on said casing and a central portion thereof forming an abutmentforsaid diaphragm structure.

10. Fluid transfer apparatus comprising, in combination, a casing, aresilient diaphragm structure having lateral rigidityperipherally.

. l11. Fluid transfer apparatus comprising. in t combination, a cuppedcasing, a resilient metal centrally apertured diaphragm having lateralrigidity and certain spring characteristics resiliently mounted at itsperiphery on said casing in a substantially fluid-tight manner to formthere with a pump chamber, inlet and outlet valves communicating withthe chamber, an operating rod extending through the aperture in saiddiaphragm and anchored thereto by resilient gasket means with one endcomprising projecting means in. the chamber and the other end extendingoutwardly from said diaphragm free from any bearing support andcomprising operating means, and a leaf-like spring structure comprisinga washer-like spring member having outer portions thereof supported onsaid casing and of a diameter less than the internal diameter of thechamber, said spring structure biasing said diaphragm with saidprojecting means engaged in the central aperture of said washer-likespring member with the greatest transverse dimension of said projectingmeans being less than the diameter of the spring aperture.

12. Fluid transfer apparatus comprising, in combination, a cuppedcasing, a resilient metal centrally apertured diaphragm having lateralrigidity and certain spring characteristics resil.

' iently mounted at its periphery on said casing in a substantiallyfluid-tight manner by resilient gasket means to form therewith a pumpchamber, inlet and outlet valves communicating with the chamber, anoperating rod extending through the aperture in said diaphragm andanchored thereto by resilient gasket means with one end comprisingprojecting means in the-chamber and the other end extending outwardlyfrom said diaphragm free from any bearing support and comprisingoperating means, a plurality of circumferentially spaced seats insidethe chamber, and a leaf-like spring structure comprising a washer-likespring member having outer portions thereof supported on said seats andof a diameter less than the internal diameter of the chamber to providefluid passages intermediate said seats, said spring structure biasingsaid diaphragm with said projecting means eng-aged in the centralaperture of said washer-like spring member with the greatest transversedimension of said projecting means being less than the diameter of thespring aperture.

13. Fluid transfer apparatus comprising, in combination, a casing,`aresilient initially substantially flat diaphragm structure havinglateral rigidity and certain spring characteristics with outer edgesthereof mounted on'said casing latter compensate for those of the formerto atfor laterally inward movement .of outer portions of said diaphragmstructure during fiexure thereof and to form with said casing a pumpchamber, means to flex said diaphragm, and a diaphragm-biasing leaf-likespring structure comprising a cupped washer-like spring member having`certain spring characteristics substantially the reverse of those ofsaid diaphragm structure mounted'with 'outer portions thereof supportedon-said casing. said spring structure being arranged in the chamber withthe cupping thereof facing away from said diaphragm and the centralportion of the former biasing the latter so that the springcharacteristics of theformer compensate for those of the latter toattain certain net spring characteristics and assure approximatelyuniform pressure on the diaphragm flexing means throughout operativecycles.

14. Fluid transfer apparatus comprising, in'

combination, a casing, a resilient initially sub` stantially flatdiaphragm structure having lateral'rigidity and certain springcharacteristics 2lil with outer edges thereof mounted on said casing toform a pump chamber, means to flex said diaphragm, 'a diaphragm-biasingleaf-like spring structure comprising a washer-like spring member havinga substantially centrally located aperture and certain springcharacteristics substantially the reverse of those of said diaphragmstructure mounted with outer portions thereof supported onsaid casing,and thrust means between substantially the central portion of saiddiaphragm structure and said spring structure having a portionprojecting into the aperture in said spring member causing them tooperate t0- gether so that the spring characteristics of the taincertain net spring characteristics and assure approximately uniformpressure on the diaphragm exing means throughout operative 15. Fluidtransfer apparatus comprising, in combination, a casing, a resilientinitially substantially flat diaphragm structure having lateral rigidityand certain spring characteristics with outer edges thereof mounted onsaid casing to form a pump chamber, means to flex said diaphragm, adiaphragm-biasing leaf-like spring structure comprising a washer-likespring member having a substantially centrally located aperture andcertain spring characteristics substantially the reverse of those ofsaid diaphragm structure mounted with outer portions thereof supportedon said casing, and thrust means between substantially the centralportion of said diaphragm structure and said spring structure having'aportion projecting into the aperture in said spring member causing themto operate together so that the spring characteristics of the lattercompensate for those of the former to attain certain net springcharacteristics and assure approximately uniform pressure on thediaphragm flexing means throughout operative cycles. said spring memberbeing of a diameter less thanv the internal diameter of the chamber andthe greatest transverse dimensionof said protially fluid-tight manner byresilient gasket means to form a pump chamber, means to flex I saiddiaphragm, anda diaphragm-biasing leaf-v like spring structurecomprising a cupped washerlike spring member having certainspringcharacteristics substantially the reverse of those oi said diaphragmstructure mounted with outer portions thereof supported on said casing,said spring structure being arranged in the chamber with the cuppingthereof facing away from said diaphragm and the central portion of theformer biasing the latter so that the spring characteristics of theformer compensate for those ot the latter to attain certain net springcharacteristics and assure approximately uniform pressure on thediaphragm fiexingmeans throughout operative cycles.

17. Fluid transfer apparatuscomprising in combination, a casing, acentrally apertured resilient initially substantially flat diaphragmstructure having lateral rigidity and certain spring characteristicswith outer edges thereof resiliently mounted on said casing in asubstantially uid-tight manner by resilient gasket means to Vi'orm apump chamber. thrust means anchored in the aperture in said diaphragm by'resilient gasketmeans and projecting into vthe chamber, means to iexsaid diaphragm, and a .diaphragm-biasing leaf-like spring structurecomprising a washer-like spring member having certain. springcharacteristics substantially the reverse of those of said diaphragmstructure mounted with outer portions thereof supported on said Acasingand having said thrust means -received in the aperture therein causingsaid diaphragm structure andsaid spring structure to operatetogether sothat the spring characteristics of th latter compensate for those of theformer to'attain certain net spring characteristics and assureapproximately uniform pressure` on the diaphragm exing means -throughoutoperative cycles.

WARNER T. TABB.

